Body Fat Percentage and Weight Loss

One to two pounds per week is the general guideline for safe, sustainable weight loss. While this has been the guideline most used in weight loss, tracking body fat percentage will give you a better idea of how your body composition is changing.

Weight loss alone does not necessarily mean that you are losing body fat. Weight loss without exercise and specifically strength training will lead to a loss of lean body mass (muscle) as well. If you really want to lose body fat you have to not only eat better and burn more calories through cardiovascular exercise and more everyday movement, but you also need to do strength training to build and keep muscle, otherwise up to 27% of your weight loss can come from muscle loss. And remember that muscle is metabolic tissue, it requires energy to function. The more of it you have, the more calories your body burns throughout the day, increasing your metabolism and your fat loss efforts.

Assuming that you are strength training as part of your weight loss routine, you can use the following formula to calculate approximately how much weight you need to lose to reach a desired body fat percentage. Desired body weight = Lean body weight/(1-desired body fat percentage)

If you are 180lbs and currently 25% body fat (135lbs lean mass and 45lbs body fat) with a goal of getting to 20% body fat, the calculation would look like this:

Desired body weight = 135/(1-0.20) = 168.75lbs

This person would need to lose approximately 11.25lbs (180 – 168.75) to reach their goal of 20% body fat.

What is the average body fat percentages for men and women?

First, remember that the ideal body fat percentage for men and women are different. Women need a higher body fat percentage then men.

For men the average range is between 15 and 20%. For women 25 to 30%.

Using these guidelines combined with the formula above you can now calculate how much weight loss is required for you to get to a specific body composition. You will need to have a body fat test done. A lot of digital weight scales have this function built in nowadays but we also have a device for this measurement at the front desk.

You would only want to check your body fat percentage about once per month as it takes a little while for the percent of body fat to see any major changes.

Tracking your weight alone does not tell you whether or not the weight loss comes from body fat or from lean body mass. Tracking body fat percentage will help you determine a better picture of what is actually changing with your body composition so use both together to know what is really going on!